Time series data, such as seismic data etc. were previously compressed in the “steim1” or “steim2” formats as specified by the Incorporated Research Institutions for Seismology (IRIS). These formats are specified as part of the SEED format, first published Feb. 25, 1988. In steim1 format, each 32 bit integer numeric value is delta coded by replacing it with the difference between the current and previous value. This generally results in numbers closer to zero because the original analog signal does not change much between samples. Then whenever four successive values can represented in 8 bits or less, or two successive values can be represented in 16 bits or less, these values are packed into a single 32 bit word. An additional 2 bits are needed to record which packing format was used. These additional bits are packed into a separate 16 bit word. The steim2 format is based on a similar idea, but allows delta coded values to be encoded and packed using 4, 5, 6, 8, 10, 15, or 30 bits per value.
Time series data is also compressed with a general purpose data compressors utilizing mixing algorithms or filtering techniques often used to compress audio files.